This invention relates to the means for insuring full closure of the head access door in a cartridge for use in a disk drive machine when the door is not positioned in an open position by an external force.
Standardized cartridges, including a single memory disk assembly, are well known in the art, a typical structure for such a cartridge being that shown in U.S. Pat. No. 3,526,884. Such cartridges are adapted to be inserted in a disk drive machine used as peripheral equipment for a computer (e.g., see U.S. Pat. No. 3,800,325), which machine is adapted to engage and open an access door in a housing of the cartridge (which opening of the door releases means in the cartridge for restricting movement of the disk assembly in the cartridge) to engage a hub portion of the disk assembly and rotate the disk assembly in the housing, and to move a head in the drive unit through the access door to write or read information in a magnetizable coating on the surface of the disk assembly.
Typically the housing for such a cartridge has generally parallel circular top and bottom walls and a cylindrical edge wall between the edges of the top and bottom walls, and has an opening through the edge and top walls affording access for the head of the disk drive machine to read or write on the disk assembly. The access door for the housing includes first and second portions disposed generally at right angles to each other, with the first portion and the part of the second portion adjacent thereto being adapted to close the opening when the door is in its closed position. The second portion of the door extends across the center of the top wall of the housing and is hingedly mounted on the top wall at its end opposite the first portion to afford movement of the door between closed and open positions. The means for restricting movement of the disk assembly in the housing when the cartridge is removed from the disk drive machine includes a plunger mounted in the top wall of the housing adjacent the hub portion of the disk and under the second portion of the door for movement axially of the disk assembly, and a compression spring between the top wall and the plunger for biasing the plunger to a storage position against the disk assembly, and for thereby pressing the disk assembly into frictional engagement against the bottom wall of the cartridge. The door has a lug projecting from the second portion of the door and adapted to engage the plunger after movement of the door has begun from its closed toward its open position to move the plunger to a retracted position out of engagement with the hub portion and thereby allow rotation of the disk assembly by the disk drive machine.
Because of this linkage between the door and the plunger, the movement of the plunger toward the disk under the influence of the compression spring when the access door is allowed to close will also move the door to a semiclosed position, after which the linkage may telescope together to allow movement of the door to its fully closed position. The length of the extended linkage is not adapted to fully close the door or hold the door in its fully closed position, however, to be sure that the plunger can press the disk assembly firmly against the bottom wall of the housing without any restraining effect that could otherwise be exerted by the linkage between the door and the plunger.
Thus such prior art cartridges have included means for fully closing the access door and holding it in its fully closed position after the compression spring has moved the door to its semiclosed position. These means have included means for pivotably mounting the first portion of the door on the second portion of the door, means for biasing the first portion of the door toward the edge wall, and latching members on the first portion of the door adapted to move along cam surfaces and into detents in the edge wall of the housing to fully close the door under the influence of the biasing means after the compression spring has positioned the door in its semiclosed position (e.g., the structure shown in U.S. Pat. No. 3,526,884).